LT1521 - 300mA Low Dropout Regulators with Micropower Quiescent Current and Shutdown


  • Dropout Voltage: 0.5V
  • Output Current: 300mA
  • Quiescent Current: 12µA
  • No Protection Diodes Needed
  • Adjustable Output from 3.8V to 20V
  • Fixed Output Voltages: 3V, 3.3V, 5V
  • Controlled Quiescent Current in Dropout
  • Shutdown IQ = 6µA
  • Reverse Battery Protection
  • No Reverse Current
  • Thermal Limiting

Typical Application

LT1521 Typical Application
LT1521 Typical Application


The LT1521/LT1521-3/LT1521-3.3/LT1521-5 are low dropout regulators with micropower quiescent current and shutdown. These devices are capable of supplying 300mA of output current with a dropout voltage of 0.5V.Designed for use in battery-powered systems, the low quiescent current, 12uA operating and 6uA in shutdown, makes them an ideal choice. The quiescent current is well controlled; it does not rise in dropout as it does with many other low dropout PNP regulators.

Other features of the LT1521/LT1521-3/LT1521-3.3/LT1521-5 include the ability to operate with very small output capacitors. They are stable with only 1.5uF on the output while most older devices require between 10uF and 100uF for stability. Small ceramic capacitors can be used,enhancing manufacturability. Also, the input may be connected to voltages lower than the output voltage, including negative voltages, without reverse current flow from output to input. This makes the LT1521 series ideal for backup power situations where the output is held high and the input is low or reversed. Under these conditions only 5uA will flow from the output pin to ground.


For complete and up to date package information and drawings, please refer to our packaging page

SOT-223, SO-8, MS-8

LT1521 Package Drawing
LT1521 Package Drawing
LT1521 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT1521CMS8 MSOP 8 C $2.65 $2.20 View
LT1521CMS8-3 MSOP 8 C $2.65 $2.20 View
LT1521CMS8-3.3 MSOP 8 C $2.65 $2.20 View
LT1521CMS8-3.3#PBF MSOP 8 C $2.65 $2.20 View
LT1521CMS8-3.3#TR MSOP 8 C $2.26 View
LT1521CMS8-3.3#TRPBF MSOP 8 C $2.26 View
LT1521CMS8-3#PBF MSOP 8 C $2.65 $2.20 View
LT1521CMS8-3#TR MSOP 8 C $2.26 View
LT1521CMS8-3#TRPBF MSOP 8 C $2.26 View
LT1521CMS8-5 MSOP 8 C $2.65 $2.20 View
LT1521CMS8-5#PBF MSOP 8 C $2.65 $2.20 View
LT1521CMS8#PBF MSOP 8 C $2.65 $2.20 View
LT1521CS8 SO 8 C $2.75 $2.20 View
LT1521CS8-3 SO 8 C $2.75 $2.20 View
LT1521CS8-3.3 SO 8 C $2.75 $2.20 View
LT1521CS8-3.3#PBF SO 8 C $2.75 $2.20 View
LT1521CS8-3.3#TR SO 8 C $2.26 View
LT1521CS8-3.3#TRPBF SO 8 C $2.26 View
LT1521CS8-3#PBF SO 8 C $2.75 $2.20 View
LT1521CS8-3#TR SO 8 C $2.26 View
LT1521CS8-3#TRPBF SO 8 C $2.26 View
LT1521CS8-5 SO 8 C $2.75 $2.20 View
LT1521CS8-5#PBF SO 8 C $2.75 $2.20 View
LT1521CS8-5#TR SO 8 C $2.26 View
LT1521CS8-5#TRPBF SO 8 C $2.26 View
LT1521CS8#PBF SO 8 C $2.75 $2.20 View
LT1521CS8#TR SO 8 C $2.26 View
LT1521CS8#TRPBF SO 8 C $2.26 View
LT1521CST-3 SOT 3 C $2.36 $1.90 View
LT1521CST-3.3 SOT 3 C $2.36 $1.90 View
LT1521CST-3.3#PBF SOT 3 C $2.36 $1.90 View
LT1521CST-3.3#TR SOT 3 C $1.96 View
LT1521CST-3.3#TRPBF SOT 3 C $1.96 View
LT1521CST-3#PBF SOT 3 C $2.36 $1.90 View
LT1521CST-3#TR SOT 3 C $1.96 View
LT1521CST-3#TRPBF SOT 3 C $1.96 View
LT1521CST-5 SOT 3 C $2.36 $1.90 View
LT1521CST-5#PBF SOT 3 C $2.36 $1.90 View
LT1521CST-5#TR SOT 3 C $1.96 View
LT1521CST-5#TRPBF SOT 3 C $1.96 View
LT1521IS8 SO 8 I $3.35 $2.65 View
LT1521IS8-3 SO 8 I $3.35 $2.65 View
LT1521IS8-3.3 SO 8 I $3.35 $2.65 View
LT1521IS8-3.3#PBF SO 8 I $3.35 $2.65 View
LT1521IS8-3.3#TR SO 8 I $2.71 View
LT1521IS8-3.3#TRPBF SO 8 I $2.71 View
LT1521IS8-3#PBF SO 8 I $3.35 $2.65 View
LT1521IS8-3#TR SO 8 I $2.71 View
LT1521IS8-3#TRPBF SO 8 I $2.71 View
LT1521IS8-5 SO 8 I $3.35 $2.65 View
LT1521IS8-5#PBF SO 8 I $3.35 $2.65 View
LT1521IS8-5#TR SO 8 I $2.71 View
LT1521IS8-5#TRPBF SO 8 I $2.71 View
LT1521IS8#PBF SO 8 I $3.35 $2.65 View
LT1521IS8#TR SO 8 I $2.71 View
LT1521IS8#TRPBF SO 8 I $2.71 View
LT1521IST-3 SOT 3 I $3.15 $2.55 View
LT1521IST-3.3 SOT 3 I $3.15 $2.55 View
LT1521IST-3.3#PBF SOT 3 I $3.15 $2.55 View
LT1521IST-3.3#TR SOT 3 I $2.61 View
LT1521IST-3.3#TRPBF SOT 3 I $2.61 View
LT1521IST-3#PBF SOT 3 I $3.15 $2.55 View
LT1521IST-3#TRPBF SOT 3 I $2.61 View
LT1521IST-5 SOT 3 I $3.15 $2.55 View
LT1521IST-5#PBF SOT 3 I $3.15 $2.55 View
LT1521IST-5#TRPBF SOT 3 I $2.61 View
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

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  • Low Current Regulator
  • Regulator for Battery-Powered Systems
  • Post Regulator for Switching Supplies

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